The Human Immune System Flashcards
Nonspecific Defense
Contains 2 lines of defense
First Line of Defense
- A barrier that helps prevent pathogens from entering the body
- Skin
- Mucous membrane
- Cilia in respiratory system
- Stomach acid
Second Line of Defense
- Limit the spread of invaders in advance of specific immune responses
1. Inflammatory response
2. Phagocytes
3. Interferons
Inflammatory response
- Swelling, redness, warmth, soreness
- To increase the blood supply to the area, and increase nutrients(oxygen and white blood cells)
- Histamine
- Increase body temperature speeds up immune system
Histamine
- Triggers vasodilation (enlargement of blood vessels)
- increases blood supply to area, bring phagocytes
- responsible for symptoms of the cold
vasodilation
Enlargement of blood vessels
Phagocytes
-eat invading microbes
Macrophages
-A type of white blood cell that extend pseudopods and engulf microbes
Interferons
Chemicals released by the immune sytem to block against VIRAL infections
Specific Defense
- Third line of defense
- Specific and consists of lymphocytes
Lymphatic tissue
spleen, lymph nodes, tonsils, adenoids
Antigens
Anything that triggers an immune response
B lymphocytes
-Produce antiBodies against a SPECIFIC antigen –> humoral response
T lymphocytes
Fight pathogens by hand-to-hand combat —> cell mediated response
Humoral response
B lymphocytes
Cell mediated response
T lymphocytes
Antibodies
-neutralize antigens by binding to them and by forming an antigen-antibody complex that can be eaten by phagocytes
Clonal selection
- Mechanism in immunity
- Once an antigen binds to a specific B or T lymphocyte, the antibody becomes very metabolically active and clones itself
- Then it differentiates into plasma cells and memory cells
Plasma cells
- Fight antigens immediately - primary immune response
- Don’t live long
Memory cells
- Remain circulating in the blood for a lifetime
- specific for every viral infection you’ve gotten or vaccination
- immunological memory
Immunological memory
-prevents you from getting any specific viral infection more than once
Types of immunity
Passive and active
Passive immunity
- TEMPORARY
- Borrowed antibodies that don’t survive for long
- ex/ maternal antibodies
Active immunity
- PERMANENT
- You make the antibodies yourself
Cross-match
Before someone receives a transfusion of blood, samples of the recipient’s and donor’s blood must be mixed in the lab to determine and ensure compatibility
AIDs
-take advantage of a collapsed immune system
HIV
- attacks helper T cells
- retrovirus; transcribes in reverse in cell
Allergies
- hypersensitive immune responses to certain substances called allergens
- release of excessive amounts of histamine
Anaphylactic shock
A life-threatening allergic response
Autoimmune diseases
- Caused by a mistake of the immune system
- Can’t distinguish between self and nonself
- Perceives certain structures in the body as foreign and produces antibodies to attack them
